Steven Kwartin is still not bored with Phish. And the 52-year-old tax attorney from Hollywood, Fla., was just one head in a sea of at least 25,000 fans of the jam band who descended upon Saratoga Performing Arts Center for the final show of the newly reunited group’s sold-out summer show. Kwartin analyzes performances of the song “Tweezer” like some guys do a touchdown pass or a shortstop error.